Final answer:
Descent with modification refers to the evolutionary process by which organisms change over generations due to the inheritance of advantageous traits through natural selection. This leads to populations gradually adapting to their environments, a key aspect of Darwin's theory of evolution.
Step-by-step explanation:
Descent with modification is a fundamental concept of Darwin's theory, which postulates that all species are related and gradually change over time. Darwin's observations concluded that through the mechanism of natural selection, certain traits become more common in a population because they confer an advantage in survival and reproduction. These advantageous traits are passed on to the next generation, leading to gradual changes in the population, or descent with modification.
Moreover, Darwin and Wallace's theory emphasized that because of the inherited variation among individuals in a population, those with characteristics that are better suited to their environment are more likely to survive and reproduce, thus passing these favorable characteristics on to their offspring.
The process of descent with modification ensures that over generations, populations evolve to have traits that better suit their environment. This concept is supported by scientific disciplines such as genetics, where shared characteristics can be observed, and by the geological and fossil records that provide evidence for the common ancestry of life. As environments change over time, this could lead to the diversification of species due to the different evolutionary paths taken as a result of differing environmental pressures.